Highly active antiretroviral therapy (HAART) usually involves three or more antiretroviral drugs from two or more different classes or a regimen that includes the use of a drug called abacavir (Ziagen). Unfortunately, this powerful combination cannot suppress HIV indefinitely, and its effectiveness depends on a number of factors: how quickly a person infected with HIV begins treatment, how strictly the patient adheres to the treatment regimen, their treatment history (whether or not they had been treated with other, less effective therapies), and whether they have any other infections, such as hepatitis C or tuberculosis.

Despite this, the decrease in the rate of progression of HIV and the number of deaths from AIDS after the introduction of HAART has been large and dramatic. Recently, a group of researchers decided to assess the continuing effectiveness of HAART. The results of their study, published in the October 18, 2003 issue of The Lancet found that HAART continues to decrease the rate of progression to AIDS and death from AIDS in people infected with HIV.

About the study

The researchers enrolled 7740 patients with HIV infection for whom the date of their infection could be reliably estimated. Their goal was to assess the continuing effects of HAART on both survival and progression to AIDS. They did this by comparing the effects of age at the onset of infection, means of exposure to the virus (injection drug use or sexual contact), gender, and initial symptoms for three time periods:

  • Pre-1997 (before the introduction of HAART therapy
  • 1997-1998 (during which time HAART therapy was in limited use)
  • 1999-2001 (widespread use of HAART)

The findings

Compared with the pre-HAART era (pre-1997), the researchers found that the risk of death from HIV/AIDS decreased by 50% in the limited use era (1997-1998) and by more than 80% in the widespread use era (1999-2001). The most significant decline occurred immediately after the introduction of HAART and continued, albeit by more moderate numbers, throughout the widespread use era.

They also found that the risk of progression to AIDS fell substantially from the pre-HAART era (46%) to the widespread use era (13%). This decline was also most pronounced immediately after the introduction of HAART.

One surprising finding was that during the widespread use era, the death rate for those who had contracted HIV through injection drug use was four-times greater than it was for men who had contracted the disease through homosexual contact. They also found that the risk of progression to AIDS was higher in older patients (over 45 at the time of infection) compared to younger patients during the pre-HAART era. This difference all but disappeared by 2001.

How does this affect you?

The study found that, at least in the developed world, treatment with HAART continues to contribute to increased survival rates for people infected with HIV. In fact, researchers say that because of the availability of HAART, nine out of every ten people infected with HIV can now expect to live for more than ten years, regardless of their age. This is great news.

As for the increase in death rates for those who contracted HIV through injection drug use, the researchers offered several possible explanations:

  • Injection drug users may be more likely to also be infected with hepatitis C, another deadly disease.
  • Injection drug users may have less access to HAART.
  • Injection drug users may respond less well to HAART, or their adherence to the complicated regimen is lower, which, in turn affects their rate of response to the therapy.

Unfortunately, HAART is not a panacea, and survival times are climbing more slowly than they used to. Again, there may be a number of reasons for this. HAART is expensive and difficult to adhere to. Its side effects can be severe, and some patients simply cannot tolerate it over the long term. For some patients, HAART fails to decrease their HIV viral load to below detectable levels. This translates into an increased risk of disease progression for them and an increased risk of disease transmission for others. And, new, drug-resistant strains can infect patients who have already contracted other strains.

Cleary, we cannot rest on the success of HAART. Research into new therapies must continue. An effective vaccine must be found. In the battle against HIV/AIDS, HAART, imperfect as it is, is the biggest gun we have, but we can’t trust a virus as slippery and virulent as HIV not to build a bigger one.